This invention relates to heat exchangers, and more particularly, to brazed heat exchangers having side pieces.
Many heat exchangers today employ several parallel runs of straight tubing of flattened cross section which are spaced from one another. Between the straight runs of tubing, fins exist which may be either plate fins or serpentine fins. The runs define at least one row of tube runs and the first run in the row defines one side and the last run in the row defines the opposite side. Typically, fins will be bonded to both the first and last rows to extend outwardly of the sides of the resulting core. Where the runs are made up of individual pieces of tubing, headers will receive respective ends of each of the individual pieces of tubing. Where the runs are defined by straight lengths of a serpentine wound length of tubing, headers will be placed on one end of both the first and last runs and 180xc2x0 turns formed in the tubing will interconnect the ends of the intermediate runs. Again, fins will extend between the runs as well as outwardly from opposite sides of the first and last runs.
Side pieces are also typically employed in these constructions. In many instances the side pieces will extend fully between the headers just outwardly of the outermost fins of the first and last runs to provide rigidity to the heat exchanger once it is brazed or otherwise has its components bonded together and serve to protect the fins that are exterior of the tube runs as well as rigidify the heat exchanger. Similar side pieces will be employed in heat exchangers of the serpentine type but obviously cannot extend between the headers because there will be only one header at each of the first and last runs.
In the usual case, such heat exchangers are placed in a fixture with the tubes and fins being introduced into the fixture in alternating fashion where the tubes are individual pieces of tubing. Where the heat exchanger is of a serpentine form, the fins are introduced between the adjacent runs and at the sides of the core. Side pieces are placed against the fins at the sides of the core. The parts are held in place by fixtures. Then the fixtures are run through a brazing furnace or the like to unite the components.
A substantial cost in the manufacture of such heat exchangers is setting up the headers, tubes, fins and side pieces in the fixtures. Considerable expense in fabrication could be avoided where the components themselves are self-fixturing, allowing the use of separate fixtures to be done away with.
One type of self-fixturing heat exchanger of this general sort is disclosed in commonly assigned application Ser. No. 09/778,310, filed Feb. 7, 2001, entitled xe2x80x9cHeat Exchangerxe2x80x9d in the name of Stephen Memory et al. The entire disclosure of the Memory et al. application is herein incorporated by reference. It discloses a self-fixturing heat exchanger but does not deal with the issue of side pieces. Consequently, protection for ends of the fins that extend beyond the first and last tube runs and the rigidifying effect that accompanies side pieces are not present.
The present invention is directed to provide a new and improved, self-fixturing side piece for use in heat exchangers such as, but not limited to, those disclosed in the Memory et al. application.
It is the principal object of the invention to provide a new and improved side piece construction for heat exchangers. More specifically, it is an object of the invention to provide a new and improved heat exchanger with a self-fixturing side piece.
An exemplary embodiment of the invention achieves the foregoing objects in a heat exchanger that includes a core having at least one row of a plurality of spaced, parallel, straight runs of flattened tubing including spaced first and last runs and each defining an associated side on opposite sides of said row, fins bridging the spacing between each of the plurality of runs and extending outwardly oppositely from outwardly facing sides of the first and last runs and bonded to the tubing, and a side piece at at least one side of the row and sandwiching the fins thereat against one of the first and last runs. The invention includes the improvement wherein the side piece has a length sufficient to extend substantially between the ends of the at least one of the first or last tube runs and inturned ends hooked over the one run at its ends.
In a preferred embodiment, the side piece is brazed to the one run and to at least some of the fins between the side piece and the one run to provide rigidity to the heat exchanger.
In a highly preferred embodiment, there are a pair of the side pieces, one at each side of the row.
A preferred embodiment of the invention contemplates that the inwardly directed ends of the side pieces include notches having a width just slightly larger than the minor dimension of the first and last runs at its respective ends.
In one embodiment, the tube runs, the fins, and the side pieces are aluminum and are bonded together by brazing.
One embodiment of the invention contemplates that the runs be defined by straight lengths of a serpentine formed piece of tubing.
In another embodiment, the runs are defined by individual lengths of straight tubing.
In one embodiment of the invention, the fins are serpentine fins.
In another embodiment of the invention the fins are plate fins.
Other objects and advantages will become apparent from the following specification taken in connection with the accompanying drawings.